zabbix3.2升级3.4报错Database error

zabbix3.2版本升级到zabbix3.4版本后打开页面报错，报错内容如下

Database error
The frontend does not match Zabbix database. Current database version (mandatory/optional): 3020000/3020000. Required mandatory version: 3040000. Contact your system administrator.

解决办法：

进入数据库

mysql> show databases;
mysql> use zabbix;
mysql> update dbversion set mandatory=3040000;
mysql> flush privileges;

重新打开web即可解决